1. The Field of the Invention
The present invention is directed to a container/casing for a battery, and, more particularly, a lightweight container for use in cooperation with relatively flat stackable cells therewithin. It is contemplated that the cells comprise rechargeable lithium ion cells with a polymer based electrolyte, or, alternatively, with a liquid electrolyte of a composition known in the art.
2. The Prior Art
Lithium ion rechargeable batteries for use in numerous applications, including consumer available devices, are well known in the art. Indeed, such lithium batteries are desirable over other conventional rechargeable batteries (e.g., nickel cadmium, nickel metal hydride) due to their lighter weight, high energy density and overall efficiency, among other things.
Although lithium batteries are relatively light, it is typically desirable to have as light a battery as possible--without, of course, sacrificing any significant operational attributes of the battery. At present, current lithium ion batteries having the necessary capacity and cyclability for use in devices such as portable telephones and notebook/lap-top computers, among others, are fabricated with a liquid electrolyte. While lithium batteries fabricated with a polymer based electrolyte are known in the art, their use in applications requiring relatively high capacities and cyclabilities have not been implemented due to a lack of desired conductivity and other electrical properties, as well as the lack of a means for encasing such a battery.
When using a liquid electrolyte, it is necessary that the battery casing be constructed of a rather rigid and, accordingly, a relatively heavy material. Furthermore, the casings are typically nickel plated steel so as to reduce the likelihood of corrosion, and are rigid so as to help preclude buckling of the casing caused from internal pressures. In addition to the casing, the conventional rechargeable lithium batteries require spring plates which not only add weight to the battery, but which take up valuable volume within the cell which could otherwise be occupied by the other internal components (electrodes and electrolyte) toward yet additional capacity. Furthermore, the fabrication of such batteries is relatively expensive and each application requires specific, relatively complicated configurations for the outer casing, as well as for the internal components.